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Phloem-carbohydrate assay

Geeta Bharathan geeta at life.bio.sunysb.edu
Thu Feb 28 11:45:52 EST 2002

I got this from a friend who has worked on phloem proteins in cucurbits:

We collected phloem proteins which are
abundantly present in cucurbits.  The p-protein PP1
gels when exposed to oxygen and makes it difficult to
harvest phloem exudate.  For a carbohydrate assay I
would choose a plant with less phloem proteins and
avoid cucurbits.

Karin Jacobsen

On 27 Feb 2002, Bill Williams wrote:

> Dear Plant-Eders,
> We've just incorporated a phloem carbohydrate-analysis unit to our 
> introductory biology sequence. Students cut off six-week cucurbit 
> leaves, collect the exudate into micro-capillary tubes, and use 
> anthrone reagent to test for total carbohydrates, comparing against 
> sucrose standards using Sequoia-Turner spectrophotometers. It worked 
> (although only after we changed from water to 60% ethanol for 
> diluting our exudate and making our standards), but the students had 
> great difficulty getting enough exudate. Does anyone know tricks for 
> increasing the amount of exudate? Are there particular species or 
> varieties that work better than others? Tricks about light/dark 
> cycles or time of day or watering regimes or something?
> Regards,
> Bill Williams
> -- 
> ________________________
> William E. Williams WEWilliams at smcm.edu
> Biology Department
> Saint Mary's College of Maryland
> 18952 E. Fisher Rd.
> Saint Mary's City, MD  20686-3001
> (240)895-4365
> ---

 Geeta Bharathan
 Assistant Professor
 Department of Ecology and Evolution
 State University of New York
 Stony Brook, NY 11794-5245
 www: http://life.bio.sunysb.edu/ee/geeta/

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